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root/jsr166/jsr166/src/jsr166y/ForkJoinTask.java

Comparing jsr166/src/jsr166y/ForkJoinTask.java (file contents):
Revision 1.82 by dl, Thu Jan 26 18:15:12 2012 UTC vs.
Revision 1.89 by dl, Mon Apr 9 13:11:44 2012 UTC

#	Line 5 | Line 5
5		*/
6
7		package jsr166y;
8	+
9		import java.io.Serializable;
10		import java.util.Collection;
11		import java.util.List;
#	Line 93 | Line 94 | import java.lang.reflect.Constructor;
94		* performs the most common form of parallel invocation: forking a set
95		* of tasks and joining them all.
96		*
97	<	* <p>In the most typical usages, a fork-join pair act like a a call
97	>	* <p>In the most typical usages, a fork-join pair act like a call
98		* (fork) and return (join) from a parallel recursive function. As is
99		* the case with other forms of recursive calls, returns (joins)
100		* should be performed innermost-first. For example, {@code a.fork();
#	Line 115 | Line 116 | import java.lang.reflect.Constructor;
116		* <p>The ForkJoinTask class is not usually directly subclassed.
117		* Instead, you subclass one of the abstract classes that support a
118		* particular style of fork/join processing, typically {@link
119	<	* RecursiveAction} for computations that do not return results, or
120	<	* {@link RecursiveTask} for those that do.  Normally, a concrete
121	<	* ForkJoinTask subclass declares fields comprising its parameters,
122	<	* established in a constructor, and then defines a {@code compute}
123	<	* method that somehow uses the control methods supplied by this base
124	<	* class. While these methods have {@code public} access (to allow
125	<	* instances of different task subclasses to call each other's
126	<	* methods), some of them may only be called from within other
127	<	* ForkJoinTasks (as may be determined using method {@link
128	<	* #inForkJoinPool}).  Attempts to invoke them in other contexts
129	<	* result in exceptions or errors, possibly including
130	<	* {@code ClassCastException}.
119	>	* RecursiveAction} for most computations that do not return results,
120	>	* {@link RecursiveTask} for those that do, and {@link
121	>	* CountedCompleter} for those in which completed actions trigger
122	>	* other actions.  Normally, a concrete ForkJoinTask subclass declares
123	>	* fields comprising its parameters, established in a constructor, and
124	>	* then defines a {@code compute} method that somehow uses the control
125	>	* methods supplied by this base class. While these methods have
126	>	* {@code public} access (to allow instances of different task
127	>	* subclasses to call each other's methods), some of them may only be
128	>	* called from within other ForkJoinTasks (as may be determined using
129	>	* method {@link #inForkJoinPool}).  Attempts to invoke them in other
130	>	* contexts result in exceptions or errors, possibly including {@code
131	>	* ClassCastException}.
132		*
133		* <p>Method {@link #join} and its variants are appropriate for use
134		* only when completion dependencies are acyclic; that is, the
#	Line 137 | Line 139 | import java.lang.reflect.Constructor;
139		* {@link Phaser}, {@link #helpQuiesce}, and {@link #complete}) that
140		* may be of use in constructing custom subclasses for problems that
141		* are not statically structured as DAGs. To support such usages a
142	<	* ForkJoinTask may be atomically <em>marked</em> using {@link
143	<	* #markForkJoinTask} and checked for marking using {@link
144	<	* #isMarkedForkJoinTask}. The ForkJoinTask implementation does not
145	<	* use these {@code protected} methods or marks for any purpose, but
142	>	* ForkJoinTask may be atomically <em>tagged</em> with a {@code
143	>	* short} value using {@link #setForkJoinTaskTag} or {@link
144	>	* #compareAndSetForkJoinTaskTag} and checked using {@link
145	>	* #getForkJoinTaskTag}. The ForkJoinTask implementation does not
146	>	* use these {@code protected} methods or tags for any purpose, but
147		* they may be of use in the construction of specialized subclasses.
148		* For example, parallel graph traversals can use the supplied methods
149	<	* to avoid revisiting nodes/tasks that have already been
150	<	* processed. Also, completion based designs can use them to record
151	<	* that one subtask has completed. (Method names for marking are bulky
152	<	* in part to encourage definition of methods that reflect their usage
150	<	* patterns.)
149	>	* to avoid revisiting nodes/tasks that have already been processed.
150	>	* Also, completion based designs can use them to record that subtasks
151	>	* have completed. (Method names for tagging are bulky in part to
152	>	* encourage definition of methods that reflect their usage patterns.)
153		*
154		* <p>Most base support methods are {@code final}, to prevent
155		* overriding of implementations that are intrinsically tied to the
#	Line 197 | Line 199 | public abstract class ForkJoinTask<V> im
199		* methods in a way that flows well in javadocs.
200		*/
201
200	–	/**
201	–	* The number of times to try to help join a task without any
202	–	* apparent progress before giving up and blocking. The value is
203	–	* arbitrary but should be large enough to cope with transient
204	–	* stalls (due to GC etc) that can cause helping methods not to be
205	–	* able to proceed because other workers have not progressed to
206	–	* the point where subtasks can be found or taken.
207	–	*/
208	–	private static final int HELP_RETRIES = 32;
209	–
202		/*
203		* The status field holds run control status bits packed into a
204		* single int to minimize footprint and to ensure atomicity (via
205		* CAS).  Status is initially zero, and takes on nonnegative
206	<	* values until completed, upon which status holds value
207	<	* NORMAL, CANCELLED, or EXCEPTIONAL. Tasks undergoing blocking
208	<	* waits by other threads have the SIGNAL bit set.  Completion of
209	<	* a stolen task with SIGNAL set awakens any waiters via
210	<	* notifyAll. Even though suboptimal for some purposes, we use
211	<	* basic builtin wait/notify to take advantage of "monitor
212	<	* inflation" in JVMs that we would otherwise need to emulate to
213	<	* avoid adding further per-task bookkeeping overhead.  We want
214	<	* these monitors to be "fat", i.e., not use biasing or thin-lock
215	<	* techniques, so use some odd coding idioms that tend to avoid
216	<	* them.
206	>	* values until completed, upon which status (anded with
207	>	* DONE_MASK) holds value NORMAL, CANCELLED, or EXCEPTIONAL. Tasks
208	>	* undergoing blocking waits by other threads have the SIGNAL bit
209	>	* set.  Completion of a stolen task with SIGNAL set awakens any
210	>	* waiters via notifyAll. Even though suboptimal for some
211	>	* purposes, we use basic builtin wait/notify to take advantage of
212	>	* "monitor inflation" in JVMs that we would otherwise need to
213	>	* emulate to avoid adding further per-task bookkeeping overhead.
214	>	* We want these monitors to be "fat", i.e., not use biasing or
215	>	* thin-lock techniques, so use some odd coding idioms that tend
216	>	* to avoid them, mainly by arranging that every synchronized
217	>	* block performs a wait, notifyAll or both.
218	>	*
219	>	* These control bits occupy only (some of) the upper half (16
220	>	* bits) of status field. The lower bits are used for user-defined
221	>	* tags.
222		*/
223
224		/** The run status of this task */
225		volatile int status; // accessed directly by pool and workers
226	<	static final int NORMAL      = 0xfffffffc;  // negative with low 2 bits 0
227	<	static final int CANCELLED   = 0xfffffff8;  // must be < NORMAL
228	<	static final int EXCEPTIONAL = 0xfffffff4;  // must be < CANCELLED
229	<	static final int SIGNAL      = 0x00000001;
230	<	static final int MARKED      = 0x00000002;
226	>	static final int DONE_MASK   = 0xf0000000;  // mask out non-completion bits
227	>	static final int NORMAL      = 0xf0000000;  // must be negative
228	>	static final int CANCELLED   = 0xc0000000;  // must be < NORMAL
229	>	static final int EXCEPTIONAL = 0x80000000;  // must be < CANCELLED
230	>	static final int SIGNAL      = 0x00010000;  // must be >= 1 << 16
231	>	static final int SMASK       = 0x0000ffff;  // short bits for tags
232
233		/**
234		* Marks completion and wakes up threads waiting to join this
235	<	* task, also clearing signal request bits. A specialization for
238	<	* NORMAL completion is in method doExec
235	>	* task.
236		*
237		* @param completion one of NORMAL, CANCELLED, EXCEPTIONAL
238		* @return completion status on exit
#	Line 244 | Line 241 | public abstract class ForkJoinTask<V> im
241		for (int s;;) {
242		if ((s = status) < 0)
243		return s;
244	<	if (U.compareAndSwapInt(this, STATUS, s, (s & ~SIGNAL)|completion)) {
245	<	if ((s & SIGNAL) != 0)
244	>	if (U.compareAndSwapInt(this, STATUS, s, s | completion)) {
245	>	if ((s >>> 16) != 0)
246		synchronized (this) { notifyAll(); }
247		return completion;
248		}
#	Line 267 | Line 264 | public abstract class ForkJoinTask<V> im
264		} catch (Throwable rex) {
265		return setExceptionalCompletion(rex);
266		}
267	<	while ((s = status) >= 0 && completed) {
268	<	if (U.compareAndSwapInt(this, STATUS, s, (s & ~SIGNAL)|NORMAL)) {
272	<	if ((s & SIGNAL) != 0)
273	<	synchronized (this) { notifyAll(); }
274	<	return NORMAL;
275	<	}
276	<	}
267	>	if (completed)
268	>	s = setCompletion(NORMAL);
269		}
270		return s;
271		}
272
273		/**
274	+	* Tries to set SIGNAL status unless already completed. Used by
275	+	* ForkJoinPool. Other variants are directly incorporated into
276	+	* externalAwaitDone etc.
277	+	*
278	+	* @return true if successful
279	+	*/
280	+	final boolean trySetSignal() {
281	+	int s = status;
282	+	return s >= 0 && U.compareAndSwapInt(this, STATUS, s, s | SIGNAL);
283	+	}
284	+
285	+	/**
286		* Blocks a non-worker-thread until completion.
287		* @return status upon completion
288		*/
289		private int externalAwaitDone() {
290	+	boolean interrupted = false;
291		int s;
292	<	if ((s = status) >= 0) {
293	<	boolean interrupted = false;
294	<	synchronized (this) {
295	<	while ((s = status) >= 0) {
291	<	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
292	>	while ((s = status) >= 0) {
293	>	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
294	>	synchronized (this) {
295	>	if (status >= 0) {
296		try {
297		wait();
298		} catch (InterruptedException ie) {
299		interrupted = true;
300		}
301		}
302	+	else
303	+	notifyAll();
304		}
305		}
300	–	if (interrupted)
301	–	Thread.currentThread().interrupt();
306		}
307	+	if (interrupted)
308	+	Thread.currentThread().interrupt();
309		return s;
310		}
311
312		/**
313	<	* Blocks a non-worker-thread until completion or interruption or timeout.
313	>	* Blocks a non-worker-thread until completion or interruption.
314		*/
315	<	private int externalInterruptibleAwaitDone(long millis)
310	<	throws InterruptedException {
315	>	private int externalInterruptibleAwaitDone() throws InterruptedException {
316		int s;
317		if (Thread.interrupted())
318		throw new InterruptedException();
319	<	if ((s = status) >= 0) {
320	<	synchronized (this) {
321	<	while ((s = status) >= 0) {
322	<	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
323	<	wait(millis);
324	<	if (millis > 0L)
325	<	break;
321	<	}
319	>	while ((s = status) >= 0) {
320	>	if (U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
321	>	synchronized (this) {
322	>	if (status >= 0)
323	>	wait();
324	>	else
325	>	notifyAll();
326		}
327		}
328		}
329		return s;
330		}
331
328	–
332		/**
333		* Implementation for join, get, quietlyJoin. Directly handles
334		* only cases of already-completed, external wait, and
335	<	* unfork+exec.  Others are relayed to awaitJoin.
335	>	* unfork+exec.  Others are relayed to ForkJoinPool.awaitJoin.
336		*
337		* @return status upon completion
338		*/
339		private int doJoin() {
340		int s; Thread t; ForkJoinWorkerThread wt; ForkJoinPool.WorkQueue w;
341		if ((s = status) >= 0) {
342	<	if (!((t = Thread.currentThread()) instanceof ForkJoinWorkerThread))
343	<	s = externalAwaitDone();
344	<	else if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue).
345	<	tryUnpush(this) || (s = doExec()) >= 0)
343	<	s = awaitJoin(w, wt.pool);
344	<	}
345	<	return s;
346	<	}
347	<
348	<	/**
349	<	* Helps and/or blocks until joined.
350	<	*
351	<	* @param w the joiner
352	<	* @param p the pool
353	<	* @return status upon completion
354	<	*/
355	<	private int awaitJoin(ForkJoinPool.WorkQueue w, ForkJoinPool p) {
356	<	int s;
357	<	ForkJoinTask<?> prevJoin = w.currentJoin;
358	<	w.currentJoin = this;
359	<	for (int k = HELP_RETRIES; (s = status) >= 0;) {
360	<	if ((w.queueSize() > 0) ?
361	<	w.tryRemoveAndExec(this) :        // self-help
362	<	p.tryHelpStealer(w, this))        // help process tasks
363	<	k = HELP_RETRIES;                 // reset if made progress
364	<	else if ((s = status) < 0)            // recheck
365	<	break;
366	<	else if (--k > 0) {
367	<	if ((k & 3) == 1)
368	<	Thread.yield();               // occasionally yield
369	<	}
370	<	else if (k == 0)
371	<	p.tryPollForAndExec(w, this);     // uncommon self-help case
372	<	else if (p.tryCompensate()) {         // true if can block
373	<	try {
374	<	int ss = status;
375	<	if (ss >= 0 &&                // assert need signal
376	<	U.compareAndSwapInt(this, STATUS, ss, ss | SIGNAL)) {
377	<	synchronized (this) {
378	<	if (status >= 0)      // block
379	<	wait();
380	<	}
381	<	}
382	<	} catch (InterruptedException ignore) {
383	<	} finally {
384	<	p.incrementActiveCount();     // re-activate
385	<	}
342	>	if (((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)) {
343	>	if (!(w = (wt = (ForkJoinWorkerThread)t).workQueue).
344	>	tryUnpush(this) || (s = doExec()) >= 0)
345	>	s = wt.pool.awaitJoin(w, this);
346		}
347	+	else
348	+	s = externalAwaitDone();
349		}
388	–	w.currentJoin = prevJoin;
350		return s;
351		}
352
#	Line 395 | Line 356 | public abstract class ForkJoinTask<V> im
356		* @return status upon completion
357		*/
358		private int doInvoke() {
359	<	int s; Thread t;
359	>	int s; Thread t; ForkJoinWorkerThread wt;
360		if ((s = doExec()) >= 0) {
361	<	if (!((t = Thread.currentThread()) instanceof ForkJoinWorkerThread))
361	>	if ((t = Thread.currentThread()) instanceof ForkJoinWorkerThread)
362	>	s = (wt = (ForkJoinWorkerThread)t).pool.awaitJoin(wt.workQueue,
363	>	this);
364	>	else
365		s = externalAwaitDone();
402	–	else {
403	–	ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
404	–	s = awaitJoin(wt.workQueue, wt.pool);
405	–	}
366		}
367		return s;
368		}
#	Line 439 | Line 399 | public abstract class ForkJoinTask<V> im
399		* any ForkJoinPool will call helpExpungeStaleExceptions when its
400		* pool becomes isQuiescent.
401		*/
402	<	static final class ExceptionNode extends WeakReference<ForkJoinTask<?>>{
402	>	static final class ExceptionNode extends WeakReference<ForkJoinTask<?>> {
403		final Throwable ex;
404		ExceptionNode next;
405		final long thrower;  // use id not ref to avoid weak cycles
#	Line 457 | Line 417 | public abstract class ForkJoinTask<V> im
417		* @return status on exit
418		*/
419		private int setExceptionalCompletion(Throwable ex) {
420	<	int h = System.identityHashCode(this);
421	<	final ReentrantLock lock = exceptionTableLock;
422	<	lock.lock();
423	<	try {
424	<	expungeStaleExceptions();
425	<	ExceptionNode[] t = exceptionTable;
426	<	int i = h & (t.length - 1);
427	<	for (ExceptionNode e = t[i]; ; e = e.next) {
428	<	if (e == null) {
429	<	t[i] = new ExceptionNode(this, ex, t[i]);
430	<	break;
420	>	int s;
421	>	if ((s = status) >= 0) {
422	>	int h = System.identityHashCode(this);
423	>	final ReentrantLock lock = exceptionTableLock;
424	>	lock.lock();
425	>	try {
426	>	expungeStaleExceptions();
427	>	ExceptionNode[] t = exceptionTable;
428	>	int i = h & (t.length - 1);
429	>	for (ExceptionNode e = t[i]; ; e = e.next) {
430	>	if (e == null) {
431	>	t[i] = new ExceptionNode(this, ex, t[i]);
432	>	break;
433	>	}
434	>	if (e.get() == this) // already present
435	>	break;
436		}
437	<	if (e.get() == this) // already present
438	<	break;
437	>	} finally {
438	>	lock.unlock();
439		}
440	<	} finally {
476	<	lock.unlock();
440	>	s = setCompletion(EXCEPTIONAL);
441		}
442	<	return setCompletion(EXCEPTIONAL);
442	>	ForkJoinTask<?> p = internalGetCompleter(); // propagate
443	>	if (p != null && p.status >= 0)
444	>	p.setExceptionalCompletion(ex);
445	>	return s;
446	>	}
447	>
448	>	/**
449	>	* Exception propagation support for tasks with completers.
450	>	*/
451	>	ForkJoinTask<?> internalGetCompleter() {
452	>	return null;
453		}
454
455		/**
#	Line 539 | Line 513 | public abstract class ForkJoinTask<V> im
513		* @return the exception, or null if none
514		*/
515		private Throwable getThrowableException() {
516	<	if (status != EXCEPTIONAL)
516	>	if ((status & DONE_MASK) != EXCEPTIONAL)
517		return null;
518		int h = System.identityHashCode(this);
519		ExceptionNode e;
#	Line 557 | Line 531 | public abstract class ForkJoinTask<V> im
531		Throwable ex;
532		if (e == null || (ex = e.ex) == null)
533		return null;
534	<	if (e.thrower != Thread.currentThread().getId()) {
534	>	if (false && e.thrower != Thread.currentThread().getId()) {
535		Class<? extends Throwable> ec = ex.getClass();
536		try {
537		Constructor<?> noArgCtor = null;
#	Line 624 | Line 598 | public abstract class ForkJoinTask<V> im
598		}
599
600		/**
601	<	* Report the result of invoke or join; called only upon
628	<	* non-normal return of internal versions.
601	>	* Throws exception, if any, associated with the given status.
602		*/
603	<	private V reportResult() {
604	<	int s; Throwable ex;
605	<	if ((s = status) == CANCELLED)
606	<	throw new CancellationException();
607	<	if (s == EXCEPTIONAL && (ex = getThrowableException()) != null)
603	>	private void reportException(int s) {
604	>	Throwable ex = ((s == CANCELLED) ?  new CancellationException() :
605	>	(s == EXCEPTIONAL) ? getThrowableException() :
606	>	null);
607	>	if (ex != null)
608		U.throwException(ex);
636	–	return getRawResult();
609		}
610
611		// public methods
#	Line 657 | Line 629 | public abstract class ForkJoinTask<V> im
629		* @return {@code this}, to simplify usage
630		*/
631		public final ForkJoinTask<V> fork() {
632	<	ForkJoinWorkerThread wt;
661	<	(wt = (ForkJoinWorkerThread)Thread.currentThread()).
662	<	workQueue.push(this, wt.pool);
632	>	((ForkJoinWorkerThread)Thread.currentThread()).workQueue.push(this);
633		return this;
634		}
635
#	Line 675 | Line 645 | public abstract class ForkJoinTask<V> im
645		* @return the computed result
646		*/
647		public final V join() {
648	<	if (doJoin() != NORMAL)
649	<	return reportResult();
650	<	else
651	<	return getRawResult();
648	>	int s;
649	>	if ((s = doJoin() & DONE_MASK) != NORMAL)
650	>	reportException(s);
651	>	return getRawResult();
652		}
653
654		/**
#	Line 690 | Line 660 | public abstract class ForkJoinTask<V> im
660		* @return the computed result
661		*/
662		public final V invoke() {
663	<	if (doInvoke() != NORMAL)
664	<	return reportResult();
665	<	else
666	<	return getRawResult();
663	>	int s;
664	>	if ((s = doInvoke() & DONE_MASK) != NORMAL)
665	>	reportException(s);
666	>	return getRawResult();
667		}
668
669		/**
#	Line 720 | Line 690 | public abstract class ForkJoinTask<V> im
690		* @throws NullPointerException if any task is null
691		*/
692		public static void invokeAll(ForkJoinTask<?> t1, ForkJoinTask<?> t2) {
693	+	int s1, s2;
694		t2.fork();
695	<	t1.invoke();
696	<	t2.join();
695	>	if ((s1 = t1.doInvoke() & DONE_MASK) != NORMAL)
696	>	t1.reportException(s1);
697	>	if ((s2 = t2.doJoin() & DONE_MASK) != NORMAL)
698	>	t2.reportException(s2);
699		}
700
701		/**
#	Line 859 | Line 832 | public abstract class ForkJoinTask<V> im
832		* @return {@code true} if this task is now cancelled
833		*/
834		public boolean cancel(boolean mayInterruptIfRunning) {
835	<	return setCompletion(CANCELLED) == CANCELLED;
835	>	return (setCompletion(CANCELLED) & DONE_MASK) == CANCELLED;
836		}
837
838		public final boolean isDone() {
#	Line 867 | Line 840 | public abstract class ForkJoinTask<V> im
840		}
841
842		public final boolean isCancelled() {
843	<	return status == CANCELLED;
843	>	return (status & DONE_MASK) == CANCELLED;
844		}
845
846		/**
#	Line 887 | Line 860 | public abstract class ForkJoinTask<V> im
860		* exception and was not cancelled
861		*/
862		public final boolean isCompletedNormally() {
863	<	return status == NORMAL;
863	>	return (status & DONE_MASK) == NORMAL;
864		}
865
866		/**
#	Line 898 | Line 871 | public abstract class ForkJoinTask<V> im
871		* @return the exception, or {@code null} if none
872		*/
873		public final Throwable getException() {
874	<	int s = status;
874	>	int s = status & DONE_MASK;
875		return ((s >= NORMAL)    ? null :
876		(s == CANCELLED) ? new CancellationException() :
877		getThrowableException());
#	Line 948 | Line 921 | public abstract class ForkJoinTask<V> im
921		}
922
923		/**
924	+	* Completes this task normally without setting a value. The most
925	+	* recent value established by {@link #setRawResult} (or {@code
926	+	* null} by default) will be returned as the result of subsequent
927	+	* invocations of {@code join} and related operations.
928	+	*
929	+	* @since 1.8
930	+	*/
931	+	public final void quietlyComplete() {
932	+	setCompletion(NORMAL);
933	+	}
934	+
935	+	/**
936		* Waits if necessary for the computation to complete, and then
937		* retrieves its result.
938		*
#	Line 960 | Line 945 | public abstract class ForkJoinTask<V> im
945		*/
946		public final V get() throws InterruptedException, ExecutionException {
947		int s = (Thread.currentThread() instanceof ForkJoinWorkerThread) ?
948	<	doJoin() : externalInterruptibleAwaitDone(0L);
948	>	doJoin() : externalInterruptibleAwaitDone();
949		Throwable ex;
950	<	if (s == CANCELLED)
950	>	if ((s &= DONE_MASK) == CANCELLED)
951		throw new CancellationException();
952		if (s == EXCEPTIONAL && (ex = getThrowableException()) != null)
953		throw new ExecutionException(ex);
#	Line 985 | Line 970 | public abstract class ForkJoinTask<V> im
970		*/
971		public final V get(long timeout, TimeUnit unit)
972		throws InterruptedException, ExecutionException, TimeoutException {
973	<	// Messy in part because we measure in nanos, but wait in millis
974	<	int s; long millis, nanos;
975	<	Thread t = Thread.currentThread();
976	<	if (!(t instanceof ForkJoinWorkerThread)) {
977	<	if ((millis = unit.toMillis(timeout)) > 0L)
978	<	s = externalInterruptibleAwaitDone(millis);
979	<	else
980	<	s = status;
981	<	}
982	<	else if ((s = status) >= 0 && (nanos = unit.toNanos(timeout)) > 0L) {
983	<	long deadline = System.nanoTime() + nanos;
984	<	ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
985	<	ForkJoinPool.WorkQueue w = wt.workQueue;
986	<	ForkJoinPool p = wt.pool;
987	<	if (w.tryUnpush(this))
988	<	doExec();
989	<	boolean blocking = false;
973	>	if (Thread.interrupted())
974	>	throw new InterruptedException();
975	>	// Messy in part because we measure in nanosecs, but wait in millisecs
976	>	int s; long ns, ms;
977	>	if ((s = status) >= 0 && (ns = unit.toNanos(timeout)) > 0L) {
978	>	long deadline = System.nanoTime() + ns;
979	>	ForkJoinPool p = null;
980	>	ForkJoinPool.WorkQueue w = null;
981	>	Thread t = Thread.currentThread();
982	>	if (t instanceof ForkJoinWorkerThread) {
983	>	ForkJoinWorkerThread wt = (ForkJoinWorkerThread)t;
984	>	p = wt.pool;
985	>	w = wt.workQueue;
986	>	s = p.helpJoinOnce(w, this); // no retries on failure
987	>	}
988	>	boolean canBlock = false;
989	>	boolean interrupted = false;
990		try {
991		while ((s = status) >= 0) {
992	<	if (w.runState < 0)
992	>	if (w != null && w.runState < 0)
993		cancelIgnoringExceptions(this);
994	<	else if (!blocking)
995	<	blocking = p.tryCompensate();
994	>	else if (!canBlock) {
995	>	if (p == null || p.tryCompensate(this, null))
996	>	canBlock = true;
997	>	}
998		else {
999	<	millis = TimeUnit.NANOSECONDS.toMillis(nanos);
1013	<	if (millis > 0L &&
999	>	if ((ms = TimeUnit.NANOSECONDS.toMillis(ns)) > 0L &&
1000		U.compareAndSwapInt(this, STATUS, s, s | SIGNAL)) {
1001	<	try {
1002	<	synchronized (this) {
1003	<	if (status >= 0)
1004	<	wait(millis);
1001	>	synchronized (this) {
1002	>	if (status >= 0) {
1003	>	try {
1004	>	wait(ms);
1005	>	} catch (InterruptedException ie) {
1006	>	if (p == null)
1007	>	interrupted = true;
1008	>	}
1009		}
1010	<	} catch (InterruptedException ie) {
1010	>	else
1011	>	notifyAll();
1012		}
1013		}
1014	<	if ((s = status) < 0 ||
1015	<	(nanos = deadline - System.nanoTime()) <= 0L)
1014	>	if ((s = status) < 0 || interrupted ||
1015	>	(ns = deadline - System.nanoTime()) <= 0L)
1016		break;
1017		}
1018		}
1019		} finally {
1020	<	if (blocking)
1020	>	if (p != null && canBlock)
1021		p.incrementActiveCount();
1022		}
1023	+	if (interrupted)
1024	+	throw new InterruptedException();
1025		}
1026	<	if (s != NORMAL) {
1026	>	if ((s &= DONE_MASK) != NORMAL) {
1027		Throwable ex;
1028		if (s == CANCELLED)
1029		throw new CancellationException();
#	Line 1097 | Line 1090 | public abstract class ForkJoinTask<V> im
1090		* setRawResult(null)}.
1091		*/
1092		public void reinitialize() {
1093	<	if (status == EXCEPTIONAL)
1093	>	if ((status & DONE_MASK) == EXCEPTIONAL)
1094		clearExceptionalCompletion();
1095		else
1096		status = 0;
#	Line 1258 | Line 1251 | public abstract class ForkJoinTask<V> im
1251		protected abstract void setRawResult(V value);
1252
1253		/**
1254	<	* Immediately performs the base action of this task.  This method
1255	<	* is designed to support extensions, and should not in general be
1256	<	* called otherwise. The return value controls whether this task
1257	<	* is considered to be done normally. It may return false in
1254	>	* Immediately performs the base action of this task and returns
1255	>	* true if, upon return from this method, this task is guaranteed
1256	>	* to have completed normally. This method may return false
1257	>	* otherwise, to indicate that this task is not necessarily
1258	>	* complete (or is not known to be complete), for example in
1259		* asynchronous actions that require explicit invocations of
1260	<	* {@link #complete} to become joinable. It may also throw an
1261	<	* (unchecked) exception to indicate abnormal exit.
1260	>	* completion methods. This method may also throw an (unchecked)
1261	>	* exception to indicate abnormal exit. This method is designed to
1262	>	* support extensions, and should not in general be called
1263	>	* otherwise.
1264		*
1265	<	* @return {@code true} if completed normally
1265	>	* @return {@code true} if this task is known to have completed normally
1266		*/
1267		protected abstract boolean exec();
1268
#	Line 1335 | Line 1331 | public abstract class ForkJoinTask<V> im
1331		return wt.pool.nextTaskFor(wt.workQueue);
1332		}
1333
1334	<	// Mark-bit operations
1334	>	// tag operations
1335
1336		/**
1337	<	* Returns true if this task is marked.
1337	>	* Returns the tag for this task.
1338		*
1339	<	* @return true if this task is marked
1339	>	* @return the tag for this task
1340		* @since 1.8
1341		*/
1342	<	public final boolean isMarkedForkJoinTask() {
1343	<	return (status & MARKED) != 0;
1342	>	public final short getForkJoinTaskTag() {
1343	>	return (short)status;
1344		}
1345
1346		/**
1347	<	* Atomically sets the mark on this task.
1347	>	* Atomically sets the tag value for this task.
1348		*
1349	<	* @return true if this task was previously unmarked
1349	>	* @param tag the tag value
1350	>	* @return the previous value of the tag
1351		* @since 1.8
1352		*/
1353	<	public final boolean markForkJoinTask() {
1353	>	public final short setForkJoinTaskTag(short tag) {
1354		for (int s;;) {
1355	<	if (((s = status) & MARKED) != 0)
1356	<	return false;
1357	<	if (U.compareAndSwapInt(this, STATUS, s, s | MARKED))
1361	<	return true;
1355	>	if (U.compareAndSwapInt(this, STATUS, s = status,
1356	>	(s & ~SMASK) | (tag & SMASK)))
1357	>	return (short)s;
1358		}
1359		}
1360
1361		/**
1362	<	* Atomically clears the mark on this task.
1362	>	* Atomically conditionally sets the tag value for this task.
1363	>	* Among other applications, tags can be used as visit markers
1364	>	* in tasks operating on graphs, as in methods that check: {@code
1365	>	* if (task.compareAndSetForkJoinTaskTag((short)0, (short)1))}
1366	>	* before processing, otherwise exiting because the node has
1367	>	* already been visited.
1368		*
1369	<	* @return true if this task was previously marked
1369	>	* @param e the expected tag value
1370	>	* @param tag the new tag value
1371	>	* @return true if successful; i.e., the current value was
1372	>	* equal to e and is now tag.
1373		* @since 1.8
1374		*/
1375	<	public final boolean unmarkForkJoinTask() {
1375	>	public final boolean compareAndSetForkJoinTaskTag(short e, short tag) {
1376		for (int s;;) {
1377	<	if (((s = status) & MARKED) == 0)
1377	>	if ((short)(s = status) != e)
1378		return false;
1379	<	if (U.compareAndSwapInt(this, STATUS, s, s & ~MARKED))
1379	>	if (U.compareAndSwapInt(this, STATUS, s,
1380	>	(s & ~SMASK) | (tag & SMASK)))
1381		return true;
1382		}
1383		}
#	Line 1385 | Line 1390 | public abstract class ForkJoinTask<V> im
1390		static final class AdaptedRunnable<T> extends ForkJoinTask<T>
1391		implements RunnableFuture<T> {
1392		final Runnable runnable;
1388	–	final T resultOnCompletion;
1393		T result;
1394		AdaptedRunnable(Runnable runnable, T result) {
1395		if (runnable == null) throw new NullPointerException();
1396		this.runnable = runnable;
1397	<	this.resultOnCompletion = result;
1397	>	this.result = result; // OK to set this even before completion
1398		}
1399	<	public T getRawResult() { return result; }
1400	<	public void setRawResult(T v) { result = v; }
1401	<	public boolean exec() {
1402	<	runnable.run();
1403	<	result = resultOnCompletion;
1404	<	return true;
1399	>	public final T getRawResult() { return result; }
1400	>	public final void setRawResult(T v) { result = v; }
1401	>	public final boolean exec() { runnable.run(); return true; }
1402	>	public final void run() { invoke(); }
1403	>	private static final long serialVersionUID = 5232453952276885070L;
1404	>	}
1405	>
1406	>	/**
1407	>	* Adaptor for Runnables without results
1408	>	*/
1409	>	static final class AdaptedRunnableAction extends ForkJoinTask<Void>
1410	>	implements RunnableFuture<Void> {
1411	>	final Runnable runnable;
1412	>	AdaptedRunnableAction(Runnable runnable) {
1413	>	if (runnable == null) throw new NullPointerException();
1414	>	this.runnable = runnable;
1415		}
1416	<	public void run() { invoke(); }
1416	>	public final Void getRawResult() { return null; }
1417	>	public final void setRawResult(Void v) { }
1418	>	public final boolean exec() { runnable.run(); return true; }
1419	>	public final void run() { invoke(); }
1420		private static final long serialVersionUID = 5232453952276885070L;
1421		}
1422
#	Line 1414 | Line 1431 | public abstract class ForkJoinTask<V> im
1431		if (callable == null) throw new NullPointerException();
1432		this.callable = callable;
1433		}
1434	<	public T getRawResult() { return result; }
1435	<	public void setRawResult(T v) { result = v; }
1436	<	public boolean exec() {
1434	>	public final T getRawResult() { return result; }
1435	>	public final void setRawResult(T v) { result = v; }
1436	>	public final boolean exec() {
1437		try {
1438		result = callable.call();
1439		return true;
#	Line 1428 | Line 1445 | public abstract class ForkJoinTask<V> im
1445		throw new RuntimeException(ex);
1446		}
1447		}
1448	<	public void run() { invoke(); }
1448	>	public final void run() { invoke(); }
1449		private static final long serialVersionUID = 2838392045355241008L;
1450		}
1451
#	Line 1441 | Line 1458 | public abstract class ForkJoinTask<V> im
1458		* @return the task
1459		*/
1460		public static ForkJoinTask<?> adapt(Runnable runnable) {
1461	<	return new AdaptedRunnable<Void>(runnable, null);
1461	>	return new AdaptedRunnableAction(runnable);
1462		}
1463
1464		/**

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